Diesel fuel



, tive of an N-nitroso aromatic nitrate accordlngto the following equation:

Patented July 1941 UNITED STATE 4 2,251,157 js PATEN OFFICE -DIESEL FUEL Edwin M. Nygaard, Woodbury, N. 1., assignor to Company, Incorp rated, ;New York, N. Y., a corporation of New York No Drawing. Application October 23, 1940,

, Serial No. 882,412 i Socony-Vacnnm Oil teams. This invention has to do in a generalway with the operation of internal combustion engines and is more particularly concerned with improving the operation of compression ignition or'Diesel engines through the use of a fuel containing a characterizing ingredient which acts to improve its ignition quality In engines which operateon the Diesel cycle,- where the fuel is injected into compressed air in the cylinder and ignites spontaneously, it is important that the delay period between in- Jection andignition be short so as to promote ease of starting and smoothness of operation.

Improperly delayed ignition gives rise to the phenomenon known as knocking.

One object of this invention is to improve the ignition quality of a'Diesel fuel by admixing therewith a minor proportion of a novel compound or agent in suflicient proportion to decrease the ignition delay period of the fuel. The invention also contemplates a method for accelerating the ignition ofa fuel in a compression ignition engine by admixing with the fuel, prior to its injection into the compressed-air of the cylinder, a minor proportion of this characterizingingredient.

This invention is predicated upon the discovery that a specific group of organic nitrogen compounds, the aromatic diazo alkyl others, possesses the property of decreasing the ignition delay period of Diesel fuels when admixed therewithin minor proportions.

v The term aromatic diazo alkyl ether as used herein applies to compounds having the general formula RN=N-O.-R', wherein R is selected fromthe group consisting of aromatic radicals "and substituted aromatic radicals'and R is an ether" includes compounds in which the arcmatic group (R) is ither unsubstituted or substituted. Because of their increased stability thearomatic group (R) bearing a nitro substituent in the para position is preferred.

Further details in the procedurefor synthesizing the compounds contemplated herein may be obtained from the following example describing I the preparation of a specific compound within the preferred group.

- e v Exurras Preparation'oj p-nitro benzene diazo methyl ether A.-The sodium derivative of p-nitrophenyl nitrosamine was first prepared according to the following procedure: Two parts of p-nitroaniline were added to a solution of 2.9 parts of con- ..centrated hydrochloric acid in 12.1 parts of alkyl group. These compounds may be prepared 1 by various procedures'described in the literature '(Ber. 27. 672 (1894), Pechman and Frobenius; Ber. 36, 2505 (1903) H. Euler; Ber. 28, 227 (1895) E. Bamberger). 'One general procedure for preparing these compounds is by the reaction of.

silver diazoates with alkyi iodides. This reaction may be formulated as follows:

The silver diazoate employed in the foregoing procedure is prepared amine and silver Na Ag R-N "+isNo, Norman's-no and upon rearrangement:. I

e n-1lz no R-N=N0Ag A aforesaid,' the term ."aromatic dlazo alkyl from the sodium iderivarivative water. The mixture was cooled to 0 C., and to it was added a solution of 1 part sodium nitrite in 7.2 parts of water. The foregoing mixture was added quickly to a rapidly agitated NaOH solution heated to a temperature of -60 C. The NaOI-I solution consisted of 12.2 parts sodium hydroxide in 55.5 parts of water. The precipitated product was filtered and washed once with cold water and purified by recrystallization from 90 per cent ethyl alcohol heated to C. It

may be repre en ed bythe formula:

oiNO-i r-om vl3. Silver-p-nitrobenzene diazoate was prepared by dissolving 1.1 parts ofthe sodium deof p-nitrophenyl nitrosamine prepared by procedure A in 22.2 to 27.8 parts of water,

filtering the mixture to remove a small quantity or insoluble material and slowly adding to the giiitrate with agitation a solution of one part of silvernitrate in-about 11.1 partsof water- The 'precipitated product was filtered, washed with water, and-carefully dried on a porous plate. It may be represented by the formula:

C. Para-nitro benzene diaao methyl ether was prepared'by suspendingzLS parts of the dried 1 silver compound obtained by procedure 3 in 18.5

parts of dry diethyl ether and adding thereto 1.0part of methyl iodide dissolved in about two or three timesits own volume of dry ether. The mixture was agitated vigorously for about 3 hours, after which the precipitatedsilver iodide wasremoved by filtration and the product recovered by evaporation of the ether filtrate under vacuum. at room temperature. This final 'prod not, p-nitro benzene diazo methylether has the formula:

The corresponding ethyl derivative (p-nitro benzene diazo ethyl ether) having the formula:

was obtained inlike manner using ethyl iodide in place of methyl iodide.

To demonstrate the effectiveness of the addition a'gents contemplated herein as improvers for Cetane number determinations Increase in cetene number Cetane number of blend lereentby we 1: ad ed Substance blended with Inc] B p-Nitro benzene diam methyl ether 0.7 5. 5

"It will be seen from the foregoing tabulations that the aromatic diazo alkyl ,ethers contemplated herein are effective to improve the igni- Diesel fuel, the two compounds obtained accord of these fuels containing representative addition agents of the type contemplated herein are set forth below.

Fuel A was a straight run number 2 fuel oil possessing the following characteristics:

Gravity, A. P. I 39.8 Flash point (Pensky-Martens, F.) 172 Aniline point, "F 160.5 A. S. T. M. distillation:

Initial F 386 10% 435 90% 572 End point 614 Diesel index 63.9 Cetane number 56.5 'C'etane number determinations Percent by Cetane Increase Substanoe blended with fuel A weight number in octane ad ed of blend number p-Nitro benzene diam methyl other use 01.5 6.0 p-Nitro benzene diam ethyl ether. 0. 6 64. 5 8. 0

Fuel 3 was a catalytically'cracked fuel oil pre-' pared from Miranda gas oii and the following characteristice: Gravity, A. P. I.. 26.8 Flash point (Pensky-Martens, "F.) 78 Aniline point, '1' 101.2 A. B. 'I'. M. distillation: J

Initial F 388 10% 433 90% 555 End poin 830 Diesel index 27.1

Cetane number 21.1

tion quality of .Diesel fuels when added thereto in minor proportions. 'I'he'amount of the compound'used may be varied, depending upon the base fuel stock, etc., but in general it appears that amounts ranging from about 0.1 per cent to about 5.0 per cent will effect the desired improvement.

It is to be understfiod that the term Diesel fuel as used herein has reference to any hydrocarbon fuel adapted for use in an engine operating according to the Diesel cycle; also that the invention is not limited to the specific compounds or illustrative procedures described herein but that it includes within its scope such variations .or modifications as fairly come within the spirit of the appended claims.

I claim:

1. An improved Diesel fuel having intadmixture therewith a minor proportion of an aromatic diazo alkyl ether in sufllcient amount to improve the ignition quality of the fuel. 2. An improved Diesel fuel having in admixture therewith a minor proportion of an arcmatic diazo alkyl ether having a nitro substituent in the aromatic nucleus, the said compound being present in the fuel in an amount suftlcient to improve the ignition quality thereof.

3. Anim'proved Diesel fuel having in admixture therewith a minor proportion of a benzene diazo alkyl ether in an amount sumcient to improve the ignition quality of the fuel.

- 4. An improved Diesel fuel having in admixture therewith a minor proportion of a paranltro benzene diazo alkyl ether in an amount sumcient to improve the ignition quality of the fuel. 4 5. An improved Diesel fuel having in admixture therewith a minor proportion of para-nitro benzene diazo methyl ether in an amount sum cient to improve the ignition quality of the fuel.

6. An improved Diesel fuel havlng in admixture therewith a minor proportion of para-nitro benzene diazo ethyl ether in an amount sunlcient to improve the ignition quality of the fuel.

EDWIN M. NYGAARD. 

